This invention relates to textile yarn winding apparatus and in particular to a yarn winder which includes a yarn laying mechanism which may, for example, be in the form of a traverse guide screw and a yarn guide which is caused by engagement of a follower with the screw, to reciprocate or traverse along the length of a yarn package, e.g. a bobbin, to lay yarn evenly on the surface of the package. The yarn guide may be driven in other ways such as by a scroll, cam, belt, chain or the like. By the term "yarn" we wish to include natural and synthetic yarns, filaments, wire and the like.
It is desirable automatically to transfer yarn being wound from a full bobbin to an empty bobbin lying on the same axial plane without stopping the winding. This is particularly important when a yarn or filament is being delivered to the winder continuously at a controlled rate, e.g. directly from an extruder.
When yarn is being transferred from a full bobbin to an empty bobbin the yarn has to pass over the adjacent flanges of the two bobbins and then be wrapped around the barrel of the empty bobbin. The connecting yarn length is then severed so that the full bobbin may be doffed.
It is known to sever the yarn connecting the completed and empty bobbin between adjacent flanges of the two bobbins but this can result in a long unmanageable tail of yarn extending from the barrel of the empty bobbin which will whip around uncontrollably and become entangled with parts of the winder or entangled with the yarn being traversed along the bobbin so as to render normal winding impossible and cause yarn snarls and stoppages when the yarn is being unwound from the bobbin at the next processing stage. The problem can be further exacerbated if on transfer of the yarn from the full to the empty bobbin, the initial windings are not tightly and securely wrapped around the barrel of the empty bobbin. In order to control this long tail during winding and hold it to enable the initial windings to be tight on the barrel of the empty bobbin, specially designed extensions around which the tail of the yarn is wrapped and locked, have been provided on the bobbin flanges or have been mounted separately on the spindle to abut against the bobbin flange but these, in themselves, can cause other problems when doffing and/or transporting the full bobbins to the next processing stage.